The present invention relates to an apparatus for transferring particulate solid material between spaces which are at differential pressures, and is particularly suitable for transferring such particulate material which is oxidizable.
One of the main difficulties experienced for example in the gasification of coal dust while floating in oxygen or in oxygen-containing air, resides in the fact that problems exist in introducing the coal dust into the gasifying system which is at elevated pressures, for example at pressures of 30 atmospheres. Various proposals have been made to overcome these difficulties, and one of these suggests compacting a quantity of coal dust by means of a ram in a channel, forming a plug which is to provide a seal of the two spaces that are at differential pressures, i.e., the space from which the coal dust is fed and the gasifying system. Prior to entry into the gasifying chamber, the plug is to be comminuted again and to become mixed with the oxygen or oxygen-containing air which is to blow it into the gasifying chamber.
Another proposal suggests to admix the coal dust into the gasifying chamber via a plurality of air locks. Neither suggestion, however, has been found to be acceptable in practice. The first proposal does not eliminate the difficulties in sealing the higher-pressure and lower-pressure spaces from one another, and the second proposal encounters significant pressure losses in the air locks so that it also is disadvantageous.